1. Field of the Invention
This invention relates to methods of and apparatus for the measurement of physical properties of continuously moving metal strip without making physical contact with the moving strip.
2. Prior Art
As will be apparent from the following description, the technique of the present invention essentially makes a measurement of the velocity of an acoustic wave in the solid. This velocity is related to the Young's modulus of the material. The technique therefore may be used for measuring the Young's modulus. More widely however there are other physical properties of a material which can be determined from knowledge of the Young's modulus. In particular the Young's modulus varies with temperature and determination of Young's modulus enables the temperature of the material to be determined.
In U.S. Pat. No. 4,073,007, there is described a technique for measuring stress in a tensioned band of sheet metal, e.g. from a rolling mill, in which a disturbance is produced, e.g. by striking the band with a hammer, and the speed of propagation of the disturbance between spaced sensing locations is measured by eddy current detectors in which the effects of the disturbance on eddy currents are noted.